Syrian Foreign Minister Walid Moallem said Monday his country will not resume peace talks with Israel unless they are productive, and secure the return of the Golan Heights. Speaking at a meeting of the 57-member Organization of the Islamic Conference taking place in Damascus, Moallem said Syria will not "return to unproductive talksâ€¦ When we return to negotiations, they should bear fruit." "When Syria decides to return to negotiations, be aware it will ... be based on the liberation of the Golan," he went on. "Other than that, there will be no negotiations." Both nations have said in recent weeks they are willing to restart indirect talks that broke off in December, while staking out tough negotiating positions that appear to doom chances that that will happen. Prime Minister Binyamin Netanyahu, however, has vowed not to return the Golan, and Syria has said it refuses to talk unless it is on the agenda. Syrian President Bashar Assad said on Saturday that Israel poses the "greatest obstacle" to peace in the Middle East. About a year of indirect negotiations mediated by Turkey last year failed to produce any breakthroughs. Syria suspended them in December to protest Operation Cast Lead against Hamas terrorists in the Gaza Strip. In a newspaper interview in March, Assad said that the indirect talks with Israel failed because the Jewish state would not make a clear commitment to return all of the Golan up to the eastern shore of the Sea of Galilee. Direct talks between Syria and Israel under US auspices failed in 2000 over the same issue of the extent of an Israeli withdrawal.